Abstract 3282: Diagnostic Yield of Repeat CT Angiography in Patients with Subarachnoid Hemorrhage and Negative Initial CT and Catheter Angiograms
Bibliographic record
Abstract
Purpose: To determine the yield of repeat CT angiography for the detection of causative vascular lesions in patients with subarachnoid hemorrhage (SAH) who have negative initial CT and catheter angiograms. Methods: We conducted a retrospective review of patients who presented to our institution between January 1st, 2008 and August 1st, 2011 with SAH and negative initial CT and catheter angiograms who were examined with repeat CT angiography in order to determine the yield of this imaging modality for the detection of causative vascular lesions. Two experienced neuroradiologists evaluated the NCCTs to determine the pattern of SAH (diffuse, perimesencephalic or peripheral) and the CT angiograms (CTA) to assess for the presence of a causative vascular lesion. All differences in reader interpretation were resolved by consensus. Results: Twenty-two patients were included in our study, with a mean age of 78 years (median 59 years, range 28-78 years). Sixteen patients were male (72.7%) and 6 female (27.3%). Seventeen patients had diffuse SAH (77.3%), 4 perimesencephalic SAH (18.2%) and 1 peripheral SAH (4.5%). Mean time interval between the initial neurovascular examination and the repeat CTA was 26.5 days (median 20.5 days, range 2-150 days). The repeat CTA demonstrated a causative vascular lesion in 2 patients (9.1%), all of which had diffuse SAH (yield of 11.8%). The vascular lesions identified were 1 small pontine arteriovenous malformation and a 2-mm supraclinoid internal carotid artery aneurysm ( Figure ). The pontine arteriovenous malformation underwent radiosurgery and the internal carotid artery aneurysm underwent surgical clipping. In retrospect, none of these vascular lesions were evident in the initial CT or catheter angiograms. Conclusion: Repeat CT angiography is valuable in the evaluation of patients with diffuse SAH who have negative initial CT and catheter angiograms, demonstrating a causative vascular lesion in 11.8% of patients.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.013 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".